Flushing system for by-product coke plants



L. H. UNDERWOOD AND R. B. HITCHCDCK.

FLUSHING SYSTEM FOR BY-PRODUCT COKE PLANTS.

APPLICATION FILED NOV. 30. 1918.

5 2 SHtETS-SHEET l.

'1,309;161. Patented July 8,1919.

INVENTQRE ATTORNEY THE COLUMBIA Puwoommq co. WASHINGTON, n. L.

L. H. UNDERWOOD AND R. B. HITCHCOCK.

ELUSHING SYSTEM FOR BY-PRODUCT COKE PLANTS.

APPLECATION FILED NOV. 30, I918 Patented July 8, 1919.

2 $HEETS-SHEET 2.

ATTORNEY THE COLUMBIA I'LANOGRAPH 50., wAsmNnToN, n. c.

UNITED STATES PATENT OFFICE.

LAWRENCE H. UNDERWOOD, OF YOUNGSTOWN, AND ROBERT E. HITCHCOCK, OF

STRUTI-IERS, OHIO.

Specification of Letters Patent.

Patented July 8, 1919.

Application filed November 30, 1918. Serial No. 264,770.

To all whom it may concern:

Be it known that we, LAWRENCE H. UN- DERWOOI) and Ronnn'r B. Hrrorroooir, citizens of the United States of America, and residents, respectively, of Youngstown, county of Mahoning, and State of Ohio, and Struthers, county of Mahoning, and State of Ohio, have invented certain new and use :t'ul Improvements in Flushing Systems for By-Product Coke Plants, of which the follov-ring is a specification.

This invention relates broadly to flushing systems for by-product coke plants of the semi-direct process type, and more particularly to a hot drain tar flushing tank for such systems.

The primary object of the invention is to provide improved apparatus by means of which may be maintained any desired relative proportions of, or ratio between, the tar and liquor components of the liquid flushing medium employed for flushing foul gas mains and other apparatus of a byproduct coke plant to effect the removal of collected pitch from such mains and apparatns, to reduce the temperature of the gas at the entrance to the primary coolers, and to accomplish other results.

In flushing systems of this character as heretofore designed and operated, but little rontrol can be exercised over the proportions of the tar and weak ammoniacal liquor components of the flushing medium. In other words, wholly inadequate means has hitherto been provided whereby material fluctuations in the relative proportions of the composition, as from a point where the tar content largely predominates to the opposite extreme, could be prevented.

it may here be explained that it is desirable in the operation of such systems to maintain at most times a certain ratio be tween the tar and liquor components of the flushing medium, due to the fact that if the percentage of liquor becomes too high, the mains will become clogged with pitch;

while, on the other hand, if the p rcentage of tar becomes too high, the will not utticiently cooled before entering the in an excessive deposit oi aid coolers and a consequent shes,- a certain proportion of liquor is required in the flushing composition to cool the gases carrying the latent heat of evaporation of the water employed for cooling purposes, and a cer- 'tain proportion of tar is required to pro-- vent the accumulation of pitch in the mains. To meet these requirements demands a regulation that has been practically unattainable in prior flushing systems, and which the present invention is designed to provide.

It may be further pointed out that the mains may sometimes become clogged with pitch due to causes other than that resulting from a low tar content in the flushing medium, in which case it becomes necessary to increase the percentage out tar above that ordinarily required for a short period of time, after which the normal working ratio may be restored. The present invention has for an object to afford means for readily and promptly effecting the regulation and the changes in proportions of the constituents of the flushing medium necessitated by any condition which may arise.

A further object within the contemplation of the invention is to provide, in an apparatus of the character mentioned, automatic and continuously operating means whereby the older and heavier tar content of the flushing medium may be removed, thus preventing undue recirculation of such tar through the circulation system.

lVith these and other important objects in view, some of which will hereinafter be specifically pointed out and others of which will be made apparent to those skilled in the art, the invention resides in the features of construction, arrangement of parts and combinations of elements which will hereinafter be exemplified, reference being had to the accompanying drawings, in which Figure 1 is a top plan view of the invention with a portion of the cover broken away;

Fig. 2 is a vertical section on line 22, F ig. 1;

Fig. 3 is a section on line 33, Fig. 1;

Fig. -l: is an enlarged detail view of the V gage, and

F is an enlarged section on. line 5--5, Fig. 1.

lictcrrina said drawings, is which designating characters distinguish like parts throughout the several views 1 indicates a tank which is divided centrally by a partition 2 into two compartments A and B. Said tank may be substantially synnnetrical with respect to said par.- tition so that either of said compartments may be employed as a flushing tank in which the flushing medium collected and from which it is circulated throughout the system as needed, while the other of said compartments is simultaneously employed as a receptacle for heavy tar and liquor removed from the flushing medium. However, as shown herein for illustrative purposes, the compartment A constitutes a flushing tank to which all tar and liquor from the pri mary coolers, tar extractors, etc, is conducted through an inlet pipe and the compartment B constitutes a hot drain tank into which is delivered excess liquor and the heavy tar which accumulates through gravitation in the bottom of said compartment A, as will hereinafter be explained.

The mixture of tar and liquor constituting the flushing medium is removed from the compartment A by the usual tar flushing pumps (not shown) and is directed to the collecting mains, sprays and other parts of the system as needed, a circulation being maintained primarily for the purpose of keeping the mains and other parts of the system free from pitch.

Due to the widely different specific gravities of the tar and liquor contents of the circulation, or flushing, medium, said liquids are difiicultly miscible, and, consequently, when said medium is permitted a period of approximate rest in the flushing tank A, which is so proportioned in size to the vol ,ume of the flushing medium that such period ent invention advantage is taken of this separation in a manner which will presently be described.

The inlet {pipe 3 leads into one end of the flushing tank A near the top. Leading from the opposite end of said tank adj acent to, but above, the bottom of the latter is a pipe 4:, hereinafter termed a tar-suction nozzle, designed to receive tar to be circulated throughout the flushing system; and leading from the last-mentioned end of the tank A at an appropriate distance above said .tarsuction nozzle is a pipe 5, hereinafter termed a liquorssuction nozzle, designed to receive Said pipes 4- and 5 are preferably joined at a suitable point outside the tank, or discharge into a common pipe 6, leading to the suction side of the tar flushing pumps; or they may,

if desired, lead independently to separate ous mains and other parts of the system to .be flushed.

Located adjacent to the partition 2 at point remote from the inlet pipe 3 is a siphon by means of which the older and heavier strata of tar collected at the bottom of the flushing tank A is automatically overflowed into the hot drain compartment or tank B. Said siphon comprises an upright pipe 7 suspended from a cross T 8 which has an arm or attached pipe 9 projected hori zontally through and rigidly attached to the partition 2 at a suitable distance below the top of the latter. Said pipe 7 has its lower end located closely adjacent to the bottom of tank A, or at a level below that of the under side of the tar-suction nozzle 4, so that its open end is always sealed in the heaviest tar. This tar of greatest specific gravity is siphoned into the hot drain tank B according to certain well-known laws the basis of which is that the pressure or force exerted at any depth in a container is equal to the weight of a column of water the depth of which is the sum of the depths of each of the several liquids in the container above said depth multiplied by their specific gravities. The heaviest liquid the tar in the strata at the bottom of the tank and in which the lower end of the siphon is sealedwill flow through the siphon until its level is reduced to a depth where the weight of a column thereof is equal to the quotient obtained by dividing the specific gravity of said liquid into the sum of the depths of each of the several liquids in the tank multiplied by their several specific gravities.

As hereinbefore stated, the lower end of the siphon member 7 is located at a level below that of the bottom line of the tar-suction nozzle 4;, so that the heavy tar and coarse pitch-like material which has settled to the bottom of :the tank will be siphoned out and prevented from entering said tarsuction nozzle, whence it would otherwise be carried into the circulation system. Thus, only the lighter portions of the material in the tank are allowed to enter the circulation system where they act asa solvent for pitch which has collected in the mains.

It will be noted that it is essential that a plane or zone of separation between the highest level of the tar-suction nozzle 4 and the lowest level of the liquor-suction nozzle 5 be maintained in order that said tar-suction nozzle may constantly serve to .draw tar and that said liquor-suction nozzle may constantly serve to draw liquor plus any light ,oils carried adjacent to the level thereof. And, in order to provide for control of the proportions of tar and liquor withdrawn through the nozzles a and 5, respect' *ely, and sent throughout the circulation system, suitable regulating valves 10 and 11 are pro vided in said nozzles.

Since the proportions of tar and liquor delivered to the flushing tank A fluctuate greatly and the normal proportions withdrawn from said tank are seldom, if ever, the same as the proportions in which said constituents are delivered, and since the proportions withdrawn from time to time are necessarily varied from the normal to meet special conditions within the circulation system, all of which variations contribute to render the plane or zone of separation between the tar and the liquor in said tank variable, it becomes necessary to provide means for meeting this condition. In other words, it is necessary that means be provided whereby control of the separation plane or zone may be had for maintaining the latter at a point between the nozzles 4 and 5a result which can only be accomplished by removing from the tank excess tar or excess liquor, as the case may be. As hereinbefore indicated, excess tar is siphoned from the tank. To remove excess liquor, the same is overfiowed to the hot drain tank B.

Connected to the cross T 8 of the siphon at the side opposite that at which the horizontal pipe 9 is disposed is the horizontal end of an overflow member 12 of elbow shape which has its opposite end occupying a vertical position and terminated at a suitable distance below the top or cover 22 of the tank. Said elbow 12 constitutes an overflow for liquor, itbeing obvious that liquor entering the upper end of said elbow will flow therefrom to the compartment or tank '13 through the T 8 and pipe 9.

As is obvious, it is necessary that provision be made for varying the depth at which liquor will overflow into the tank B, it being understood that, to cause tar to be siphoned, the depth of the liquor must be increased to produce suflicient hydraulic head above the level of the lower end of the pipe 7 of the siphon to overbalance that of the tar between said level and the under side of the siphon pipe 9. On the other hand, the lowest point at which liquor may overflow'must be located at a level. at which there is insuflicient hydraulic head of liquor above the lower end of siphon pipe 7 and below the under side of siphon pipe 9 to overbalance the head of tar. In short, there must be provided a means of control whereby a separation plane or zone established between the tar and the liquor can be constantly maintained between the levels of the nozzles 41- and 5 irrespective of the percentages of tar and liquor either entering the tank A; or withdrai'v'n therefrom into the circulation system through said nozzles.

This control is effected by the provision of any suitable device for effecting adjustment or regulation of the level at which liquor will enter the overflow 12. Such device may consist of a suitable form of valve, as the sleeve valve 13 which consists of a ring or sleeve fitted in the vertical arm of the elbow l2 and vertically movable with respect to said arm, a spider 13 being provided in said ring or sleeve and having attached thereto a verti ral threaded stem 13" which is elevatable from a point without the tank.

To provide means by which the plane or zone of separation between the tar and the liquor in tank A may be visually indicated, a suitable gage is associated with. said tank. Said gage comprises a tube 1% which extends vertically from the bottom of said tank A through the cover 22, said tube being perforated or otherwise apertured throughout its length to permit contents of the tank at any level to enter uuobstructedly. Vertieally movable within said tube 14L is a float 15 carrying thereon an upright rod 16 which projects upward through a cap 17 located upon the upper end of said tube. The weight of said float and said rod is so adjusted that it will sink in the liquor of the tank and will, float upon the tar. Thus the rod 16 will serve to indicate the level of the tar, or the zone of separation, hereinbefore referred to, by its position with respect to the upper end of the float tube 14 or other fixed point. To facilitate observation, a vertical rod 18 is stationarily mounted upon the top of the tube 14 or upon an adjacent part of the tank cover 22. Such stationary rod may be provided with graduations or other indicia for indicating the level of the float when the float red assumes a position wherein its upper end is in register therewith, or a pointer, as 19, which is preferably adjustable, may be provided on said stationary red, the same be ing preferably located at a point which will indicate the level assumed by the upper end of the float red when the separation level is midway between the nozzles 4 and 5. Thus the separation level will at all times be visually indicated, enabling the operator to properly regulate the proportions of the tar and liquor retained in the tank by adjustment of the overflow hereinbefore described.

An auxiliary overflow or spillage openvided between the point where the liquid- 1;

enters the tank A through the inlet pipe 3 and the siphon, such baiile serving to retard the flow of such liquid and thereby to facilitate separation of the tar and liquor constituents.

An upright baffle 23 may also be provided on the bottom of the tank A adjacent to the tar-suction nozzle 4c for guarding the latter against the flow thereinto of the heavier tar in the bottom of said tank.

Mounted upon the top of the cross T 8 is a short upright tube or nipple 24 which extends through the tank cover 22. Said nipple is disposed in alinement with the siphon tube 7 and, in association with the latter and said T, provides a passage through which a rod, steam pipe, or other suitable device may be thrust, as occasion requires, to clear the area between the lower end of said tube 7 of any accumulations which might obstruct the entrance to said tube or retard the flow of tar into and through the siphon.

The float tube 14: not only serves as a guide for the float 15, but also to protect said float from convection and other currents set up within the tank.

lVhile a single tank divided by the partition 2 into two separate compartments or tanks is herein shown and described, it will be obvious that the number of such compartments or tanks maybe varied and that a plurality of siphons and liquor overflows such as are herein described might be employed. It will further be obvious that the invention is susceptible to various other changes and modifications falling within the scope of the appended claims.

It will be noted that the tar overflowing device constituted by the parts 7, 8 andv 9- is not a siphon in the strict sense in which that term is commonly used, and the operation of transferring tar through said parts is not strictly a siphoning action. However, since the principle of the hydrostatic balance is involved in a manner approximating that on which a siphon acts, and the function of said device is to automatically effect a transfer of material after the manner of a siphon, the terms siphon and siphoning action are herein used to designate, respectively, a transfer device of the general character of that constituted by said parts 7, 8 and 9 and the function or action of such device, rather than a true form of siphon and the action of such a siphon.

What is claimed is 1. In a flushing system of the character described, a flushing tank, means conducting a mixture of tar and liquor to said tank,

means located adjacent to the bottom ofsaid tank through which tar for flushing may be withdrawn, means located. adjacent to the top of said tank through which liquor may be withdrawn, and means whereby the plane of separation between the tar and liquor in said tank may be controlled.

2. In a flushing system of the character described, a flushing tank, means conducting a mixture of tar and liquor to said tank, means located adjacent to the bottom of said tank through which tar for flushing may be withdrawn, means located adjacent to the top of said tank through which liquor may be withdrawn, means for siphoning tar from said tank, and means for regulating the liquor level in said tank.

3. In a flushing system of the character described, a flushing tank, means eonducting a mixture of tar and liquor to said tank, means located adjacent to the bottom of said tank through which tar for flushing may be withdrawn, means located adjacent to the top of said tank through which liquor may be withdrawn, means for siphoning tar from said tank, and means for overflowing liquor from said tank, the last mentioned means being adjustable to regulate the overflow level.

4;. In a flushing system of the character described, a flushing tank, means conducting a mixture of tar and liquor to said tank, means located adjacent to the bottom of said tank through which tar for flushing may be withdrawn, means located adjacent to the top of said tank through which liquor may be withdrawn, means for siphoning tar from said tank, means for overflowing liquor from said tank, and a valve device for adjusting said overflowing'means to control the overflow level.

5. In a flushing system of the character described, a flushing tank, means conducting a miXtureLof tar and liquor to said tank, means located adjacent tothe bottom of said tank through which tar for flushing may be withdrawn, means located adjacent to the top of said tank through which liquor may be withdrawn, means for siphoning tar from said tank, said siphoning means having its receiving end located at a level below said tar-withdrawing means, and means for overflowing liquor from said tank, said overflow meansbeing adj ustableto regulate the depth of liquid in said tank for controllingthe action of the siphoning means and for controlling the proportions of tar and liquor withdrawn through said withdrawing means.

6. In a flushing system of the character described, a flushing tank, means conducting a mixture of tar and liquor to said tank, means located adjacent to the bottom of said tank through which tar for flushing may be withdrawn, means located adjacent to the top of said tank through which liquor may be withdrawn,means for siphoning tar from said. tank, means for overflowing 1iquor.c'rom said tank, means for adjusting said overflowing means to control the overflow level, and means for indicating the separation plane between the tar and liquor contents of the tank.

7. In a flushing system of the character described, a tank, means for conducting a mixture of tar and liquor to said tank, a tarwithdrawing pipe leading from said tank at a suitable point above the bottom of the latter, a liquor-withdrawing pipe leading from said tank at a suitable distance below the top of the latter, a siphon having its receiving end located below the level of the under side of said tar-withdrawing pipe, means for overflowing liquor from said tank, means for adjusting said overflow means to function at any desired level between that at which a suflicient hydraulic head to cause tar to flow through said siphon is furnished and that at which such head is insuflicient to produce such flow, and means for visually indicating the separation plane between the tar and liquor contents of said tank.

8. In a flushing systemv of the character described, a tank, means for conducting a mixture of tar and liquor to said tank, a tarwithdrawing pipe leading from said tank at a suitable point above the bottom or the latter, a liquor-withdrawing pipe leading from said tank at a suitable distance below the top of the latter, means associated with each of said pipes for controlling the volume of liquid withdrawn therethrough, a siphon having its receiving end located below the level of the under side of said tar-withdraw ing pipe, means for overflowing liquor from said tank, means for adjusting said overflow means, and a float device for indicating the separation zone between the tar and liquor contents of said tank.

9. In a flushing system of the character described a tank, means for conducting a mixture or tar and liquor to said tank, a tarwithdrawing pipe leading from said tank at a suitable point above the bottom of the latter, a liquor-withdrawing pipe leading from said tank at a suitable distance below the top of the latter, means associated with each of said pipes for controlling the volume of liquid withdrawn therethrough, a siphon having its receiving end located below the level of the under side of said tarwithdrawing pipe and its discharge end leading from said tank adjacent to the top of the latter, means for overflowing liquor from said tank, said means including an adjustable valve for regulating the level at which the liquor will overflow, and means for indicating the separation zone between the tar and liquor contents of said tank.

10. In a flushing system of the character described, a tank, means for conducting a mixture of tar and. liquor to said tank, a tarwithdrawing pipe leading from said tank at a suitable point above the bottom of the latter, a liquor-w.ithdrawing pipe leading from said tank at a suitable distance below the top of the latter, means associated with each of said pipes for controlling the volume of liquid withdrawn therethrougl'i, a siphon having its receiving end located below the level of the under side of said tar-withdraw ing pipe and its discharge end leading from said tank adjacent to the top of the latter, an elbow carried by the upper part of said siphon whereby liquor may be overflowed through said upper part, a valve for regulating the level at which liquor will so overflow, and means for indicating the separation zone between the tar and liquor contents of said tank.

11. In a flushing system of the character described, a flushing tank and a hot drain tank disposed in juxtaposition, means conducting a mixture of tar and liquor to said flushing tank, a. tar-withdrawing pipe leading from said tiushing tank at a suitable level above the bottom of the latter, a liquorwithdrawing pipe leading from said flushing tank at a suitable distance above said tarwithdrznving pipe, a siphon having its receiving end located in said flushing tank be low the level of said tar-withdrawing pipe and its discharge end extending into said hot drain tank near the top of the latter, and adjustable means for overflowing liquor from said flushing tank to said hot drain tank.

12. In a flushing system of the character described, a flushing tank and a hot drain tank disposed in juxtaposition, means con ducting a mixture of tar and liquor to said flushing tank, a tarwithdrawing pipe leading from said flushing tank at a suitable level above the bottom of the latter, a liquorwith drawing pipe leading from said flushing tank at a suitable distance above said tarwithdrawing pipe, a siphon having its receiving end located in said flushing tank bc low the level oi said tar-withdrawing pipe and its discharge end extending into said hot drain tank near the top of the latter, adjustable means for overflowingliquor from said flushing tank to said hot drain tank, and means for visually indicating the separation zone betwecn the tar and liquor contents of said flushing tank.

13. In a flushing system of the character described, a tank, a partition dividing said tank into two compartments of which one is a flushing compartment and the other a hot drain compartment, means leading into the top of said flushing compartment for conducting a mixture of tar and liquor to the latter, a air-withdrawing pipe leading from said flushing compartment at a suitable level above the bottom thereof, a liquor-withdrawing pipe leading from said flushingcon'rpartment at a suitable distance above said tarwithdrawii'ig pipe, means for transferring from said flushing compartment to the hot drain compartment the contents of the former located below the level of the tar-withdrawing pipe,- means for transferring to said hot drain compartment liquor contained in said flushing compartment to reduce the liquid level in the latter, means for adjusting the last mentioned means to control the level to which the liquid is reduced, and means for visually indicating the separation zone between the tar and liquor contents of said flushing compartment. 7

ll. In a flushing system of the character described, a tank, a partition dividing said tank into compartments of which one is a flushing compartment and the other a hot drain compartment, means leading into the top of said flushing compartment for conducting a mixture of tar and liquor to the latter, a tar-withdrawing pipe leading from said flushing compartment at a suitable level above the bottom thereof, a liqi'io'r-Withdrawing pipe leading from said flushing compartment at a suitable distance above said tar-withdrawing pipe, a siphon for conveying to said hot drain compartment contents of the flushing compartment, said siphon having its receiving end located in the lowermost strata of the contents of said flushing compartment, and means for Conducting to said hot drain compartment the uppermost contents of said flushing c'ompartment, said conducting means being adjustable to control the level at which the liquid in said flushing compartment is to be reduce'cl;

15. In a flushing system of the elfaracter described, a tank, a partition dividing said tank into two compartments of which one is a flushing compartment and the other a hot drain compartment, means leading into the top er said flushin'g compartment for conducting a mixture of tar and liquor to the latter, a tar-withdrawing pipe leading from said flushing compartment at a suitable level above the bottom thereof,- a liquorwithdraxving pipe leading from said flushing compartment at a sititable distance above said tar withdrawing pipe, a siphon for conveying to said hot drain compartment contents of the flushing compartment, said siphon havingitsreceiving end located in the lowermost strataof the contents of said flusliing; compartment, means for conducting to said hot drain compartment the uppermost contents of said flushing compartment, said conducting" means being adjustable to control the level to which the liquid in said flu'slring compartment isto be reduced, and means for indicatiirg the separation zone between the tar and liquor contents of said flushing compartment.

In testimony whe-r'eo't we affix our signa tures in presence of two witnesses.

LAYVR-ENCE H. UNDERXVOOD' ROBERT B. HITCHCOCK. lVitnesses J. A. ODE-A; ERNEST A; LEE.

Co lies of this patient ma be obtained fb'r five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

